Screw-jack.



VH. L. EWING.

SCREW JACK.

APPLICATION FILED MAY 2. |918. 1,298,316. Patented Mar. 25,1919.

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SCREW JACK.

APPucATloN man MAY 2. 19m.

Patented Mar. 25, 1919.

2 SHEETS-SHEET 2.

HARRY L. EWING, OF DALLAS, TEXAS.

SCREW-J ACK.

Application led May 2, 1918.

To all whom it may concer/n.'

Be it known that I, HARRY L. EwING, a citizen of the United States,residing at Dallas, in the county of Dallas and State of Texas, haveinvented certain new and useful Improvements in Screw-Jacks, of whichthe following is a specification.

This invention relates to jack screws and tools of like type, and hasfor its object to provide a tool of this character with a simple, strongand eiicient means for raising and lowering the screw by an operatinghandle movable transversely of the axis of the screw and adapted toactuate the screw when the tool is placed in more or less inaccessiblepositions such as below a building, in a corner or close to a wall.Between the screw and handle are placed oppositely engaging pawl andratchet devices by which the screw is turned when the swing of thehandle is limited and so insure extension or retraction of the screw.

A further object of the invention is to provide within the base of thejack screw an alarm mechanism, preferably of an audible character whichwill automatically indicate to those using the jack screw when the screwhas reached the safe limit of extension and thus prevent the danger ofprojecting the screw to an unsafe distance whereby it becomes disengagedfrom the base and is liable to fall and so endanger the lives of thepersons within the vicinity through the possibility of the object thatis being raised,

Vfalling when the screw becomes released.

With these objects in view, together with others which will appear asthe description proceeds, the invention resides in the novel formation,combination, and arrangement of parts, all as will be described morefully, hereinafter, particularly pointed out in the claims, andillustrated in the accompanying drawings, in which,

Figure 1 is a side elevation of the jack screw complete.

Fig. 2 is a central vertical sectional view of the same.

Fig. 3 is a horizontal sectional view through the head of the jack screwon the line 3--3 of Fig. 2.

' Fig. 4 is a cross sectional view of the head on the line 4.-4 of Fig.3.

Fig. 5 is a similar view on the line 5-5 of the same figure.

Fig. 6 is a horizontal sectional view of the Specification of LettersPatent.

Patented Mar. 25, 1919.

serial NQ. 232,107.

base on the line 6-6 of Fig. 2, the coupling screw being shown in itselevated position.

Fig. 7 is an elevation partly in section of the audible alarm deviceused with this invention. A

Fig. 8 is a horizontal sectional view on the line 8 8 of Fig. 2, and,

Fig. 9 is a vertical sectional view of the lower end of the operatingscrew.

In the drawings, 12 indicates the base of the tool made as usual with anexpanded foot and an upwardly inwardly tapering body provided at oneside with a grip or handle 13 by means of which the tool may betransported from place to place and adjusted in position below an objectto be moved. Through the top or smaller end of the base is formed athreaded opening extending longitudinally thereof in the axial line toreceive the actuating screw 15 which passes downwardly into the bodywhen the jack is in its lower position. At the extreme end of the top 14is a cylindrical projection 16, shouldered where it joins the base toform a support and bearing for a laterally swinging head 17 when in itslowest position, said head serving to rotate the screw 15 so that itmaybe projected and retracted.

The screw 15 at its upper end is provided with a ratchet disk 18 havingperipheral V-shaped teeth as shown in Fig. 3, said ratchet beingrotatable within the head 17 between a flange 19 in said head and thetop of the base. A'bove the ratchet 18 is a slightly reduced`cylindrical bearing 20 around which the flange 19 turns. Extendingupwardly from the bearing 20 is a square projection 21 over which isplaced a second ratchet disk 22 of similar shape to the ratchet disk 18.Preferably the ratchet disk 18, bearing 2O and projection 21 areintegrally formed with the screw.15, while an integral stem 23 projectsfrom the part 21 and has a screw thread formed on its outer end. Thehead 17 is rotatable or adapted to swing upon the bearing 20, beingsupported by the annular flange 19 resting upon the top of the ratchetdisk 18so that when the screw is rotated to move it longitudinally, thehead 17 will move with it.

The ratchet disk 22 bears upon the top of the flange 19 and is heldthereon by an anti-friction bearing 24: placed between the upper surfaceof the ratchet disk 22 and the under-surface of a bearing cap 25 that isplaced against the object to be lifted. The cap is held in placeV uponthe stem 23 and against the anti-friction bearing 24Y by a nut 26threaded on the outer end of theV stem.

the base 12 and in each side of the head are formed two horizontalnotches 27 and 28 Y is a pawl .33 formed with two fingers 34 and 35seated in said notches and pivotally heldY 'therein by .a vertical pin36, said fingers each` having a toe 37 adapted to Vengage one of thevratchet disks to turn'the screw 15 in onedirection. The tail of-thepawl is made with a vertically curved shoulder 39 fora purposesoonto be'described. A coil spring 40 between the wall 31 and the Y tail of thepawl 33 tends to maintain the toes Y Near its outer end, the head 17 isof cir- `cular cross section, as shown at 41 Fig. 5, to

of the pawls in engagementwith the teeth .of the ratchet disks. On theopposite side of Vthe head 17 is a similar pawl 33a, the fingers ofwhichunder certain conditions, engage the ratchet disks and reverse themovement of the screw.

providea bearing for a camvring 42 which encircles the tails of thepawls 33 and 33a Y 4ring 42. By thismeans the operator will atL all;times be aware of the condition lof his Vtool and know which of thepawls 33,33a are and by means of which ring the pawls are disengagedfrom the ratchet disks. This 4rlng has an eccentric or cam portion 43 onits inner circular face at a greater distance from the axis of rotationof the ring than the' remainder of said inner face Vby ywhich means whenthecam portion 43 alinesor is brought` opposite Vone of the pawlsf, the

spring 40 presses the tail of said pawl outwardly into this camportion'and causes the toes on thengers to enagage the teeth of theratchet disks. 'A half turn ofthering will'rcarry the cam surfacethereofto the' opposite side and `permit thepawl onY said side to engage theratchet disks.` This movement of the ring brings the concentric Vsurfaceof its inner face into engagement with the 'curved shoulder 39 on thetail of the pawl previously in engagement with thel ratchet ,disk andcauses said pawl to become disengaged. VMeans are Vprovided to` limitthe movement of the ring 42 to a semi-rota-Y tion, saidmeans comprisinga pin 65 projecting radially from the head 17 into Va semi-circular sloton the outer side of the One end of the headil7 projects beyond inengagement. A Thei'extreme Z end ofthe head 17 is" threaded at 44 to.receive aV threaded retaining ring 45 for holdingtheV Y cam ring A42 inplace. y

In connection with this tool is anY alarm,

preferably, audible, which is'operated by the screw when in its highestor Vmost extended position, compatible to safety, and comprisesalongitudinal Yshaft 46 carried inbearings 47 and 48 bolted or screwedagainst the wall of the base 12 within a cavity 49 formedtherein. At theupper end ofl thejshaft is affixed a latch 50 that extends crosswise ofY the shaft and adapted to berengaged by ap pawl 51 pivoted in a groove52 formed .in

thebottom of the screwl, the pawl' pro jecting a short distancebeyondwthe side of Vthe screw so asto engage the trigger .50 and rockthe shaft 46. Acoil springv 53 is suitably fitted Vto the pawlV 51yfor'the purpose of normally maintainingA it in a horizontal positionwith its end projecting beyond the 5 screw, but which will swingdownwardly! and out of the way when Vthe screw is to beV entirelyremoved Vfrom the base.

54 extending outwardly from said shaft and is provided on itsfree'end-withV a hammer.

55 to strike a bell 56 andY give an alarm The arm 54 is retracted ormoved away from the Near the. lower end of the shaft 46 issecuredan Aarmbell when the trigger isrocked by the pawl Y 51 and moved toward thebelljtocause the.

hammer to strike, by Va spring V57 coiled around the shaft 46 above thebearing 48 and secured at one end to thebearing, its opposite end beingattached to afcollar 58 threaded on the shaft and provided with a screw59 for holding said collar against movement after the spring hasbeen'properly' Y Y N Y Y f v105 In addition to thebell 56 .whichisofthe.VV gong type there is also employed `asecond-1 adjusted.

bell 60 of a continuously Yringing or lj-in, ling type which is mountedon'theV lower end of an arm 61 pivotedat 62to the base 15 and having afree upwardly V extending end that is embraced by afork631o1'iythee'nd'of the hammer arm 54, the arrangement beingjsuohi Ythat when the shaftr46. is moved away from the bell 56, the bell 60 willring throughithe action of the fork 63 on V.thev arm 61,andon the returnor striking movement of. the arm 54, the bell 60 will also ring.

The operation of the tool is self evident.l`

Then in position, a semi-rotation'of the *cam 120 means 42 willdisengage oneofthe' pa'wis 33, 33a from the ratchet disks and permit'V lthe other pawl Vnndertension of its spring v40 Y to engage said disksand upon movement 0f the head 17 the screw 15 will beturned ini onedirection; if however, the ring 42i'be given a semi-rotation in theopposite'direc tion, the pawls heretoforefreeofthe ratchet disks will beengaged therewith and the opi pos'ite pawl released. In this positionmoveisoV ment of the head 17 turns the screw in the opposite direction.The screw rotated in one direction or the other as described will causeit to be projected from or retracted into the base 12 in well knownmanner.

When the screw 15 has been projected from t'he base 12 as far as it issafe for it to go, the pawl 51 on the lower end of the screw will engagelthe trigger or latch 50 and rock the shaft 116, thereby swinging thearm 54 and the hammer 55 away from bell 56 which as soon as the pawl 51passes the latch are forcibly returned to normal position by the spring57 and the hammer caused to strike the bell 56, giving a signal that maybe audible at some distance from the pack. In addition to the alarm frombell 56 the jingling bell 60 is also caused to ring by the fork 63rocking the arm 61, to which the bell is attached. The alarm will beoperated several times if the screw continues to be rotated, so shouldthe first signal be unheeded the second or third will be sufficientwarning.

The foregoing description and the drawings have reference to what may beconsidered the preferred, or approved form of my invention. It is to beunderstood that I may make such changes in construction and arrangementand combination of parts, materials dimensions, et cetera, as may proveexpedient and fall within the scope of the appended claims.

Havin thus fully described my invention, what I c aim as new and desireto secure by Letters Patent, is:

1. In a tool of the kind described, the combination of a base, a screwlongitudinally threaded into said base, a pawl on the lower end of saidscrew projecting laterally from the side thereof, a vertical shaftwithin said base at one side of said screw, a lug on the upper end ofsaid shaft adapted to be engaged by the pawl on said screw when raisedto its highest osition for rockino' said shaft, an audible a arm withinsaid base, and a hammer on the lower end of said shaft for striking saidalarm when said shaft is rocked.

2. In a tool of the kind described, the combination of a base, a screwlongitudinally threaded into said base, a pawl on the lower end of saidscrew projecting laterally beyond the side thereof, a vertical shaftjournaled within said base substantially parallel to said screw and atone side thereof, a lug on the upper end of said shaft in position to beengaged by the pawl on the screw when the latter is raised to itshighest position and rock said sha-ft, an audible alarm secured withinsaid base, a hammer carried by the lower end of said shaft for strikingsaid alarm when the shaft is rocked, a second alarm within the basecarried by a pivot arm for actuating said alarm, and a finger on theaforesaid hammer for striking said arm when the hammer is operated.

In testimony whereof I afix my signature in presence of two witnesses.

HARRY L. EWING. Witnesses S. C. FOOTER, JN0. CLARK.

Copies of this patent may be obtained for ve cents each, by addressingthe Commissioner of Patents, Washington, D. G.

